Lorentz albert groth



UNITED STATES PATENT OFFICE.

LORENTZ ALBERT GROTH, OF LONDON, ENGLAND.

TANNING BY ELECTRICITY.

SPECIFICATION forming part of Letters latent No. 442,115, dated December 9, 1890. Application filed May 19,1888. Serial No. 274,446. (No model.)

To all whom it may concern.-

Be it known thatLLORENTZ ALBERT GROTH, civil engineer, a subject of the King of Sweden, residing at 3 Tokenhouse Buildings, in the city of London and Kingdom of Great Britain, have invented a certain Improved Process for Tanning Hides and Skins by the Aid of Electricity, of which the following is a specification.

It is well known that if a sufficiently powerful current of electricity be passed through the tanning-liquor in which hides or skins are being tanned the process of tanning is thereby hastened; but so far as I am aware all the means heretofore proposed for applying electricity practically to this purpose have been more or less unsuccessful. According to one arrangement that has been proposed the hides or skins are placed along with a suitable tanning-solution in a revolving drum provided with suitable means for passing a current of electricity through its liquid contents. In order to prevent the escape of liquid from this drum, the latter has to be hermetically closed during the operation, and as certain gases are evolved by the decomposition of the water in the liquid by the electric current or otherwise the accumulation of such gases in the said drum is liable to engender sufficient pressure to burst the same, whereby not only is material lost, but serious danger is occasioned to operatives and other persons employed in the manipulation of such apparatus.

Another objection to the employment of hermetically-closed drums is that the fermentation of the tannin g-liquid, and consequently of the hides or skins, is hastened to an injurious extent by the excessive heat developed.

The object of my invention is to obviate these defects, and for this purpose I employ a a process in which the hides or skins are moved through the tanning-liquid without being hermetically inclosed and the tanning liquid is allowed .to remain stationary.

Apparatus suitable for carrying my process into efiect is illustrated in the drawings hereto annexed, in which Figures 1 and 2 are respectively a vertical section and a plan.

A is a tank or other suitable vessel containing the tanning-solution.

B is a frame-work connected to and revolv-- ing with a vertical central shaft E and provided with bars B, furnished with pegs, pins, or hooks, to which the hides or skins are suspended so as to hang down in the tanning liquid; or, if preferred, a second frame-work, similar to B B, may be applied at the lower end of the shaft E, the lower ends of the skins being attached to such frame-work, so as to hold the said skins stretched between the two frames.

N and P are electrodes connected with a dynamo or other suitable source of electricity for the purpose of passing a current of electricity through the liquid in the tank A, while the frame-work B B rotates with the hides or skins thereon.

Instead of a special tank A, as above described, an ordinary tan-pit may be used to receive the revolving framing, and it will be understood that the necessary rotary or other motion may be imparted to such framing by worm-gearing, toothed wheel-work, or other suitable gearing, or direct by belting or otherwise, as may be most convenient.

It is obvious that the framing may be made to rotate continuously in one direction or alternately in opposite directions; or the frames or bars on which the hides or skins are hung may be caused to reciprocate in arectilinear or other direction, so as to move the hides or skins to and fro in the tanning-liquid while the electric current is acting thereon.

The apparatus is employed as follows: A number of hides or skins having been placed on the frame-work B B, as above described, tanning-liquor is admitted to the tank A until the hides or skins are immersed in such liquor. The framing B B, and consequently the hides or skins, is set in motion in the tannin g-liquid and the electrodes NP are connected to the source of electricity, so that a current of electricity is passed through the liquid. The motion of the framing and of the hides or skins is continued for about four,

days, more or less, according to circumstances, the current of electricity being maintained during that time or duringa part thereof only according to circumstances and as may be necessary for the materials under treatment. At the end of that period the tanning of the hides or skins will be completed. The

of tanning and without the danger of explosion to which closed revolving drums are, as

above mentioned, liable, while the apparatus containing or carrying the hides or skins not requiring to be water-tight as it revolves or otherwise moves in the tanning-liquid is much easier and more cheaplyconstructed, does notrequire to be so strong and heavy, requires less power to operate it, and is simpler to manipulate than the aforesaid closed-drum arrange- I ment.

I The framing and bars are preferably made of timber; but other suitable material which will not act injuriously on the tanning materials may be employed.

Inthe action of the electric current differ I ent results take place at the positive and neg tive electrodes,

respectively, and it will be seen that by moving the hides relatively to the said electrodes according to my invention and as herein specified the whole of the surfaces of the same are subjected to a uniform as distinguished from a partial .or unequal electrolytic action.

' the hides above described I the ordinary process which consists in placing in a stationary or fixed tankhaving positive a g and negative electrodes, placing the hides in} said liquid between the electrodes, passing-a current of electricity through the liquid 'and j hides, and moving and rotating the hides rela tively transverse to the electrodes, substantially Having now'particularly described and ascertained the nature of mysaid invention and in what manner the same is to be performed, I would have it understood that I do not claim, broadly, the use of electricity in tanning, or broadly apparatus for keeping or sk'insin'lnot-ion in the tanningliquid; but

Y I declare that what I do claim is- 1. The herein-described method of tanning, which consists inplacing the hides and tanning-liquid in a stationary orlixedtank, Passing a current of electricity through said liquid and the-hides, and moving the hides during the passage of said current in planes trans:

f verse to and alternatelytoward and from the positive and negativeelectrodes. p 2. The herein-described methodoftanning;

the tannin g-liquidf to the tank and. electrodes in-planes "setforthp In testimony that I claim the forego'i-n'g as :my invention- I have signed'my name in the presence of twosubscribin'gwitnesses: I Q ENTZ, LBERT. short 1 \Vitnesses: F. W; GADEJ 112 Southampton R0w,'LofizlomlVJC; :CHAS JAS. FLINT. 

